Energy beam welding with filler material

Abstract

In automatic energy beam welding, as electron beam welding, of workpiece edges which form a gap of varying width along the weld line, the amount of filler material needed for making up for the volume of the gap is determined by probing the size of the solidified weld bead at a surface of the workpiece and the rate of supply of filler material to the welding zone is controlled on the basis of the result of such determination such that the size is maintained between predetermined limits.

I claim: 
     
       1. A method of energy beam welding of two workpiece edges which form a gap the width of which varies in an irregular manner, said method comprising the steps of directing an energy beam to the gap to produce a welding zone, moving the beam relative to the workpiece to produce a weld seam including a solidified weld bead, and supplying a filler material to the welding zone to make up the volume of the gap, wherein the cross-sectional area of the solidified weld bead is determined and the feeding rate of the filler material is adjusted to keep the cross-sectional area of the weld bead between upper and lower limits. 
     
     
       2. The method as claimed in claim 1, wherein the cross sectional area of the weld bead is determined shortly after solidification of the weld bead. 
     
     
       3. The method as claimed in claim 1 or 2 wherein the cross sectional area of the weld bead is determined by periodically drawing a mechanical probe across the solidified bead. 
     
     
       4. An energy beam welding system for welding of two workpiece edges which form a gap, the width of which varies in an irregular manner, said system comprising means for controlling the rate of supply of filler material into the gap, wherein said means comprises: probe means for sensing the height (h) of a solidified weld bead produced by the welding process;   moving means for moving the probe means transversely with respect to said workpiece edges across the weld bead; and   control means responsive to said probe means, and controlling the rate of supply of filler material, said control means further comprising means for determining the cross-sectional area of the weld bead, the feeding rate being dependent on said cross-sectional area.   
     
     
       5. The system as claimed in claim 4 wherein said probe means comprise a mechanical probe physically contacting the weld bead and means for periodically pulling the probe across the solidified bead.